In general, electromagnetic fuel injection valves have chiefly been of the axial flow type in which the fuel is supplied from the axial direction as has been disclosed in the specification of U.S. Pat. No. 3,967,597.
In an injection valve of the axial flow type, the fuel passes through a penetration path formed in a stationary core of the injection valve, and is injected from a nozzle portion.
In an injection valve of the axial flow type in which only one path leads to the nozzle portion, however, the fuel stays in the injection valve. Moreover, as electric current flows through a coil constituting the magnetic circuit, the fuel which remains is heated and bubbles are generated in the fuel. With an injection valve of the abovementioned construction, the bubbles are not allowed to escape; hence, vapor lock is likely to occur.
In recent years, therefore, it has been attempted to circulate the fuel, and there has been proposed an electromagnetic injection valve of the circulation type having a fuel outflow path as disclosed in West German Patent Laid-Open No. 3,013,007.
With the above-proposed injection valve, however, the fuel intake path and the fuel outflow path are provided independently of each other and in parallel with each other, with a consequent increase in size. Therefore, it is not feasible to mount fuel injection valves in the existing mounting space of the intake manifold on which the conventional injection valves of the axial type have been mounted.
Moreover, since such an injection valve has a structure which is greatly different from the conventional injection valve of the axial flow type, parts of the conventional injection valve of the axial flow type are not utilizable, and this increases production costs.